David B. Kemp

David B. Kemp
China University of Geosciences · State Key Laboratory of Biogeology and Environmental Geology

PhD MSci

About

95
Publications
34,079
Reads
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Introduction
My research is focused on understanding the sedimentological and geochemical responses to climate change in the geological record, and establishing the rates and durations of paleoenvironmental change. I am also interested in understanding the nature of the stratigraphic record and designing and applying numerical methods of stratigraphic analysis.
Additional affiliations
January 2015 - October 2018
University of Aberdeen
Position
  • Lecturer
April 2012 - January 2015
The Open University (UK)
Position
  • NERC Research Fellow
September 2011 - March 2012
University College London
Position
  • PostDoc Position

Publications

Publications (95)
Article
The Middle Triassic is thought to have had a greenhouse paleoclimate with a few short humid phases. However, the timing of these humid events, and the extent to which orbital forcing influenced the evolution of climate, are unclear. Here, a cyclostratigraphic analysis has been carried out based on the integrated study of magnetic susceptibility, el...
Article
The timing and pattern of ecosystem recovery following the end-Permian mass extinction are still highly controversial, and a potential influence from orbital climate forcing is often not considered. To investigate this issue, a cyclostratigraphic analysis of an Anisian (Middle Triassic) marine platform succession (Guanling Formation, Yongning secti...
Article
Full-text available
Humans are primary agents of geomorphic change, and rates of anthropogenic landscape change likely far exceed the pace of change expected from natural geologic processes. Nevertheless, our understanding of the impact of humans on the natural landscape is limited by difficulties in accurately comparing past and present rates of change across wide sp...
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Silicate weathering represents a major feedback mechanism in the Earth’s climate system, helping to stabilize atmospheric CO2 levels and temperature on million-year time scales. On shorter time scales of greater relevance to understanding the fate of anthropogenic CO2, the efficacy and responsiveness of weathering is less clear. Here, we present hi...
Article
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Climate change is a critical factor affecting biodiversity. However, the quantitative relationship between temperature change and extinction is unclear. Here, we analyze magnitudes and rates of temperature change and extinction rates of marine fossils through the past 450 million years (Myr). The results show that both the rate and magnitude of tem...
Article
The PETM has previously been recorded in marine density flow sedimentary rocks of the Forties Member, Sele Formation, North Sea Basin. Two cored well sections with existing δ ¹³ C records were analysed for their total palynofloras. Using statistically defined microplankton groups and diversity data, the Sele Formation Unit S1 depositional sequence...
Article
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The early Toarcian Oceanic Anoxic Event (T-OAE, ~183 Ma) was characterized by marine deoxygenation and the burial of organic-rich sediments at numerous localities worldwide. However, the extent of marine anoxia and its impact on the sulfur cycle during the T-OAE is currently poorly understood. Here, stable sulfur isotopes of reduced metal-bound sul...
Article
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The early Toarcian oceanic anoxic event (T-OAE, ~183 Ma), also known as the Jenkyns Event, was one of the most important hyperthermal events of the Phanerozoic, caused by the large-scale release of carbon from massive volcanism and/or surficial carbon reservoirs. Organic-rich facies record the event in basins worldwide, but the precise controls on...
Article
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The Yellow River, the second longest river in China, originates in the northeastern Tibetan Plateau, flows in a contorted square-bend-shaped path through the Loess Plateau, then enters the Fenwei Graben before discharging through the Sanmen Gorge onto the North China Plain. Prior to its connection through the Sanmen Gorge, which cuts through the dr...
Article
The early Toarcian Oceanic Anoxic Event (T-OAE, or Jenkyns Event, ~183 million years ago) was a major hyperthermal and global carbon-cycle perturbation, likely associated with the release of a substantial volume of ¹²C-enriched carbon to the Earth's surface. Seawater deoxygenation and the associated deposition of organic-rich facies during this eve...
Article
Among the predicted responses to ongoing climate warming is that coastal and inland areas may experience increasingly extreme weather, with potentially more droughts and floods. Such changes will have corresponding impacts on sedimentary systems. The Paleocene-Eocene thermal maximum (PETM, ∼56 Ma) was the most abrupt extreme warming event of the Ce...
Article
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A series of biotic crises and turnovers have been recorded at the Norian/Rhaetian boundary (NRB), together with a putative perturbation to the global carbon cycle in the form of one or more negative carbon-isotope shifts. Despite this evidence, the full validation of Norian/Rhaetian climate changes has not been possible. In particular, no clear rec...
Article
Stable tungsten isotopes (δ186/184W) show great potential for tracing the cycling of materials among geological reservoirs. This work investigates the behavior of stable W isotopes on the Earth’s surface by presenting new δ186/184W data of granitic rocks, loess, river water, fluvial sediments, regolith, estuarine seawater, and marine sediments. The...
Article
Two different hypotheses, glacioeustasy and groundwater aquifer eustasy, have been proposed to explain short-term, high-amplitude sea-level oscillations during past greenhouse-dominated intervals. However, the veracity of aquifer eustasy on long-term, high amplitude sea level has never been rigorously tested. We evaluate these competing hypotheses...
Article
The early Toarcian (~183 Ma) was characterized by a prominent volcanism-induced warming event associated with a massive addition of ¹²C-enriched carbon to the ocean-atmosphere system. This warming likely contributed to marked ocean deoxygenation during this time, giving the event its name: the early Toarcian oceanic anoxic event (T-OAE). Although t...
Article
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The behaviors between δ13Cbenthic and δ18Obenthic are anti-phased after 6 Ma, and many mechanisms have been proposed to explain their behaviors. However, this question remains debated. Here, we reconstruct the interaction between mineral dust, global carbon cycle changes and the climate-cryosphere since 4 Ma. Our results suggest that Asian and/or g...
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East Asian summer monsoon (EASM) and winter monsoon (EAWM) variability on orbital time scales during the late Miocene remains poorly constrained. Climate models reveal variable responses of the EASM and EAWM to astronomical forcing, but there is a lack of empirical evidence from the geological record to validate these results. In this study, we use...
Article
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A high-precision geologic time scale is the essential key for understanding the Earth's evolutionary history and geologic processes. Astronomical tuning of orbitally forced stratigraphic records to construct high-resolution Astronomical Time Scales (ATS) has led to a progressive refinement of the geologic time scale over the past two decades. In tu...
Article
The early Toarcian (Early Jurassic, ~183 Ma) was characterized by a pronounced oceanic anoxic event (OAE), global warming, major changes in hydrological cycling and a second order mass extinction. Most studies of early Toarcian geobiology have focused on the Northern Hemisphere, and only a few studies have been carried out on strata from the southw...
Article
Studying the evolution of sea-level fluctuations, climate oscillations and tectonic movements in the Yangtze River Delta requires a reliable chronology. Here, we present the results of a comprehensive study of the magnetostratigraphy and cyclostratigraphy of a 295-m-long sediment core (ZKA2) recovered from Nantong City, Jiangsu Province, China. Ani...
Article
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Seafloor methane seepage is a significant source of carbon in the marine environment. The processes and temporal patterns of seafloor methane seepage over multi-million-year time scales are still poorly understood. The microbial oxidation of methane can store carbon in sediments through precipitation of carbonate minerals, thus providing a record o...
Conference Paper
Full-text available
Methane seepage at the seafloor is a source of carbon in the marine environment and has long been recognized as an important window into the deep geo-, hydro-, and bio-spheres. However, the processes and temporal patterns of natural methane emission over multi-million-year time scales are still poorly understood. The microbially-mediated methane ox...
Article
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Cyclostratigraphy is an important tool for understanding astronomical climate forcing and reading geological time in sedimentary sequences, provided that an imprint of insolation variations caused by Earth’s orbital eccentricity, obliquity and/or precession is preserved (Milankovitch forcing). Numerous stratigraphic and paleoclimate studies have ap...
Article
The mechanisms involved in the formation of 1- to 2-Myr-long third-order stratigraphic sequences through the Phanerozoic have been extensively debated, but the main underlying forcings remain uncertain. In this study, we investigated third-order sequences of Paleocene-Eocene age in the East China Sea Shelf Basin, identifying a prominent ∼1.2-Myr pe...
Article
Marked climate warming during the early Toarcian oceanic anoxic event (T-OAE, ~182 Ma) has been shown to have had a significant effect on the global carbon cycle and biosphere. There is also emerging evidence that a primary short-term consequence of this warming was a marked increase in hydrological cycling. In this study, we have investigated loca...
Article
Metre‐scale cycles are a common feature in Precambrian and Phanerozoic shallow water carbonate successions, and astronomically forced changes in sea‐level (Milankovitch cycles) may have been an important driver controlling their deposition. Nevertheless, the degree to which potentially low amplitude astronomically paced sea‐level oscillations may h...
Article
The palaeogeographic and tectonic setting of the Lower Jurassic Nishinakayama Formation (Toyora Group, southwest Japan) is interpreted based on new U–Pb ages for detrital zircon grains separated from a sandstone sample, combined with available provenance data. The newly obtained age spectrum of detrital zircon grains is characterized by multiple ag...
Article
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Nearly 90% of the Ediacaran Period (635–541 Ma) of the Neoproterozoic is represented by the Doushantuo Formation (DST Fm) in South China. Its lowest Member I is a 3.7 m-thick cap carbonate deposited at the termination of the Cryogenian Marinoan glaciation. The DST Fm consists of alternating organic-rich black shale and thinly bedded dolostone, and...
Article
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Mudrocks are the most common rock type at the Earth's surface, and they play a major role in informing current understanding of the palaeoenvironmental history of the planet. Their suitability for this purpose is at least partly underpinned by the assumed stratigraphic completeness of mudrock successions, and the ostensible fidelity with which they...
Article
Available online xxxx Editor: D. Vance Keywords: Toarcian carbon isotope hydrological cycling sedimentology atmospheric warming A pronounced excursion in the carbon-isotope composition of biospheric carbon and coeval seawater warming during the early Toarcian (∼183 Ma) has been linked to the large-scale transfer of 12 C-enriched carbon to the ocean...
Article
Full-text available
The Toarcian Oceanic Anoxic Event (T-OAE, 183 Ma) was characterized by enhanced carbon burial, a prominent negative carbon-isotope excursion (CIE) in marine carbonate and organic matter, and numerous geochemical anomalies. A precursor excursion has also been documented at the Pliensbachian/Toarcian boundary, but its possible causes are less constra...
Article
The early Toarcian oceanic anoxic event (T-OAE; ∼. 183. Ma) was a significant palaeoenvironmental perturbation associated with marked changes in oceanic redox conditions. However, the precise redox conditions and redox history of various water masses during the T-OAE, especially those from outside the Boreal and Tethyan realms, are unclear. To addr...
Article
Formed close to the K–Pg boundary, the Boltysh meteorite crater, Ukraine, preserves >400 m of lacustrine sedimentary rocks that include a record of the early Danian Dan-C2 hyperthermal event. Abundant pollen, spores and algae recovered from these sediments have yielded a cyclic record of plant ecology change paced by c. 21 kyr orbital precession cy...
Article
The Boltysh meteorite impact crater, Ukraine, formed at the Cretaceous-Palaeogene boundary at ca 65·2 Ma. A borehole drilled in the central part of the crater cored a >400 m thick high-resolution lacustrine succession that covers the Dan-C2 hyperthermal event associated with a negative carbon isotope excursion. Continuous terrestrial records of pas...
Article
Full-text available
Colour is an important physical property in the characterization of soil type and the description of soil profiles. Quantitative data from spectrophotometers and colorimeters have been used in soil research for this purpose, but semi-quantitative Munsell colour description remains the main method of soil colour evaluation. Low-cost digital devices...
Presentation
Full-text available
The physical characterization of soil horizons based on colour is a key diagnostic method in the description of soil profiles, and has been integrated in to diagnostic keys such as the World Reference Base for Soil Resources (WRB, 2014). The Munsell colour system has been the primary qualitative or semi-quantitative means to describe soil colour. A...
Conference Paper
Full-text available
Past hyperthermals and associated negative carbon isotope excursions (CIEs) are inferred to have had significant impact on marine environments; however the formation and changes of terrestrial ecosystems across hyperthermals are less well constrained due to the lack of complete and high-resolution data. The Boltysh impact crater, Ukraine, which for...
Article
Full-text available
At Integrated Ocean Drilling Program (IODP) Expedition 317 Site U1352, east of the South Island New Zealand, we continuously cored a 1927-m-thick Holocene-to-Eocene section where we can uniquely document downhole changes in induration and lithification in siliciclastic to calcareous fine-grained sediment using a wide range of petrological, physical...
Article
The recognition of astronomically forced (Milankovitch) climate cycles in geological archives marked a major advance in Earth science, revealing a heartbeat within the climate system of general importance and key utility. Power spectral analysis is the primary tool used to facilitate identification of astronomical cycles in stratigraphic data, but...
Article
Full-text available
A paucity of empirical non-marine data means that uncertainty surrounds the impact of climate change on terrestrial ecosystems in tropical regions beyond the last glacial period. The sedimentary fill of the Bosumtwi impact crater (Ghana) provides the longest continuous Quaternary terrestrial archive of environmental change in West Africa, spanning...
Article
Metre-scale cycles in ancient peritidal carbonate facies have long been thought to represent the product of shallow water carbonate accumulation under orbitally controlled sea-level oscillations. The theory remains somewhat controversial, however, and a contrasting view is that these cycles are the product of intrinsic, and perhaps random, processe...
Article
Full-text available
Recently observed rates of environmental change are typically much higher than those inferred for the geological past. At the same time, the magnitudes of ancient changes were often substantially greater than those established in recent history. The most pertinent disparity, however, between recent and geological rates is the timespan over which th...
Data
Supplementary Excel file containing all data used in the compilation, and references.
Data
Supplementary Figure 1, Supplementary Table 1 and Supplementary References.
Article
Mass-balance calculations indicate that a massive amount of δ13C-depleted carbon was released into the early Danian atmosphere in volumes comparable with the younger Paleocene–Eocene Thermal Maximum (PETM). This Danian hyperthermal event (the Dan-C2) has been documented from the fill of the Boltysh meteorite crater, Ukraine. Palynofloras recovered...
Article
Full-text available
The early Toarcian oceanic anoxic event (OAE) was a significant palaeoenvironmental perturbation that led to marked changes in ocean chemistry and climate, and which also had a long-lasting impact on marine ecosystems. The global significance of the event has been recognised from the widespread occurrence of a ~ 3-7‰ negative excursion in the carbo...
Article
Full-text available
Defining the time scale of abrupt events in the stratigraphic record is a primary goal of high-resolution paleoclimate analysis. A significant hurdle in this endeavor is that abrupt, i.e., millennial and submillennial, events in deep time can rarely be temporally constrained accurately owing to the typical absence of high-precision age control at t...
Article
The Boltysh meteorite impact crater formed in the Ukrainian Shield on the margin of the Tethys Ocean a few thousand years before the Cretaceous-Paleogene boundary and was rapidly filled by a freshwater lake. Sediments filling the lake vary from early lacustrine turbidites and silts to ~300 m of fine silts, organic carbon–rich muds, oil shales, and...
Article
Full-text available
Two of the most important factors that control the accumulation rate of material in carbonate platform environments on geological time scales are climate and eustasy. Accurately assessing the importance of these inter‐related factors through the study of both modern and ancient carbonate facies, however, is problematic. These difficulties arise fro...
Article
Colour is a physical property of rocks and sediments that has the potential to provide key insights into composition, and by extension the physical and chemical processes governing deposition. The rapid, non-destructive measurement of colour using spectrophotometers is an increasingly popular way of generating long datasets (i.e. >1000 data points)...
Article
Full-text available
Constraining past fluctuations in global temperatures is central to our understanding of the Earth's climatic evolution. Marine proxies dominate records of past temperature reconstructions, whereas our understanding of continental climate is relatively poor, particularly in high-latitude areas such as Antarctica. The recently developed MBT/CBT (met...
Article
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Procedures used to define an international chronostratigraphic stage boundary and to locate and ratify a Global Boundary Stratotype Section and Point (GSSP) are outlined. A majority of current GSSPs use biostratigraphic data as primary markers with no reference to any physico-chemical markers, despite the International Subcommission on Stratigraphi...
Article
Carbon isotope and palynological analysis of the fine-grained organic carbon–rich lacustrine sediments that filled the Cretaceous-Paleogene (K-Pg) boundary–age Boltysh impact crater (Ukraine) preserve a uniquely complete and detailed record of a negative carbon isotope excursion in an expanded section of the early Danian that we estimate lasted as...
Article
Compilations of sedimentation rates determined across a large range of time spans and different sedimentary environments attest to the discontinuous nature of sedimentation and support the reasoning that hiatuses pervade sedimentary successions at multiple spatial and temporal scales. The relationship between sedimentation rate and time span of obs...
Article
Full-text available
During the early Toarcian (~183 Ma ago), a high rate of organic carbon burial globally over a brief interval of time has led to the recognition of a major oceanic anoxic event (OAE). A pronounced negative excursion in the carbon-isotope composition of marine organic matter, marine carbonate and terrestrial plant material is a key feature of this ev...
Article
Oceanic anoxic events were time intervals in the Mesozoic characterized by widespread distribution of marine organic matter-rich sediments (black shales) and significant perturbations in the global carbon cycle. These perturbations are globally recorded in sediments as carbon isotope excur- sions irrespective of lithology and depositional environme...
Article
Full-text available
Expedition 317 investigated the record of global sea-level change (eustasy) within continental margin sedimentary sequences and how eustasy interacts with local forcing to produce preserved sedimentary architectures. The Canterbury Basin, on the eastern margin of the South Island of New Zealand, was selected to study these complex interactions beca...
Article
The translation of climate signals into sediments is a complex and poorly understood process, and one that is likely to be inherently nonlinear. A great deal of debate concerns the mismatch between the amplitude spectrum of astronomical insolation forcing and the amplitude spectrum of climatic signals derived from geological archives. Many ancient...